Rotary jar type well tool



June 13, 1961 Filed Sept. 22, 1958 D. D. WEBB ROTARY JAR TYPE WELL TOOL 2 Sheets-Sheet l INVENTOR 25/6264 12 M55 ATTORNEY June 13, 1961 D. D. WEBB ROTARY JAR TYPE WELL TOOL 2 Sheets-Sheet 2 Filed Sept. 22, 1958 ,D-e/ea D. 14/555 ATTORNEY Un ted States Patent v I R 2,988,147, ROTARY JAR TYPE WELL TOOL D'eri-el D. Webb, Houston, Tex., assignor to Houston Engineers, Inc, Houston, Tex., a corporation of Texas Filed Sept. '22, 1958, Ser. No. 762,593 11 Claims. (Cl; 166-478) This inveni'on relates to well tools primarily for use in relatively deep wells and more particularly to a tool which may be lowered into a-well and utilized to impart a rotary impact to a pipe string or tool jammed in the well in order to free the same and permitrecovery.

Heretofore it has been common practice to attempt to free or unscrew the joints ofpipe strings jammed in a well by applying an increasing torque to the upper end of the pipe string until the torque exerted is sufficient to loosen the joint or free the pipe or tool in order to permit recovery' thereof. Frequently, the torque applied has been insufficient to' accomplish the described purpose with the result that the torque has been increased until the backoft tool, fish or pipe string has ruptured or become damaged to such an extent that recovery thereof is impossible. Also, where' it has been attempted to apply a rotary jar or impact to thepipe string at the surface, the force resulting from such jar or impact has been substantially completely absorbed in the relatively long pipe string with the result that little or no rotary force is applied to the jammed. tool or pipe and consequently this procedure has failed to accomplish the desired purpose.

It is accordingly an object of the invention to provide a rotary jar type well tool which may be lowered into a well and coupled to the pipe or tool which is stuck therein in relatively close proximity to the point where the tool or pipe is jammed to permit the application of a rotary impact substantially directly thereto without loss of impact force due to absorption in a relatively long pipe string.

A further object of the invention is the provision of a rotary jar type well tool which may be lowered into a well at the lower end of a pipe string and coupled to the tool or pipe to be released and in which the tool of this invention provides means whereby rotary energy may be accumulated or stored in the relatively long pipe string above the tool and suddenly released toprovide' an impact force for the purpose of freeing the toolor pipe jammed in the well;

A still further object of the invention is the provision of a rotary jar type well tool which may be attached to a pipe string and disposed at any desired location in a well.

Another object of the invention is the provision of a rotary jar type well tool which may be attached to a pipe string and to a tool or'pipe to be recovered from a well without necessitating any modification whatsoever of the pipe string or conventional well tools and in which the tool of this invention is completely self-contained, thereby requiring no auxiliary equipment.

A further object of the invention is the provision of a rotary jar type well tool incorporating a cylinder and a piston movable in such cylinder and in which initial movement of the piston operates to compress a fluid in the cylinder until upon reaching a determined point in the travel of a piston the pressure is suddenly reduced to permit relatively rapid movement of the piston in the cylinder.

A stillfurther object of the invention is the provision of a rotary jar type. welL tool which may be conveniently and economically manufactured from readily available materials and which is relatively simple in construction thereby reducing the likelihood of failure to a minimum.

Further objects andadvantages of the invention will be Patented June 13, 1961 apparent from the following description taken in conjunction with the accompanying drawing wherein:

FIG. la is a longitudinal sectional view of the upper portion of a tool constructed in accordance with this invention and with the parts in the position occupied prior to operation of the tool;

FIG. 1b is a longitudinal sectional view showing the lower portion of the tool of FIG. 1a;

FIG. 2a is a longitudinal sectional view similar to FIG. la, but showing the parts in the position occupied upon the completion of the operation of the tool;

FIG. 2b is a longitudinal sectional view of the lower portion of the tool and with the parts in the final operative position;

FIG. 3 is a fragmentary elevational view showing a portion of the drive sleeve and drive member, together with the threaded connection therebetween and the cooperating impact teeth;

FIG. 4 is a sectional view taken substantially on the line 44 of FIG. la;

FIG. 5 is a sectional view taken substantially on the line 5-5 of FIG. la;

FIG. 6 is a sectional view taken substantially on the line 6-6 of FIG. 1a; and

FIG. 7 is a fragmentary longitudinal sectional view showing the piston and cylinder, together with the position occupied by the piston ring during upward movement of the cylinder relative to the piston.

With continued reference to the drawing and particularly FIGS. la and 12:, there is shown a rotary jar type well tool constructed in accordance with this invention and which may well comprise an elongated mandrel 10 having an enlarged head 11 at the upper end thereof and a threaded bore 12 in the head 11 for detachably coupling the mandrel to a pipe string. The mandrel 10 may be provided with splines 13 on the exterior surface thereof and a tubular passage 14 extends through the mandrel 10 and communicates with the threaded recess 12 in the enlarged head 11.

Slidably received on the mandrel 10 is a sleeve 15 which is provided adjacent the upper end thereof with splines 16 interengaging with the splines 13 on the mandrel 10 to permit sliding movement between the sleeve 15 and mandrel 10 but preventing relative rotation therebetween. The sleeve 15 is provided adjacent the lower end thereof with a fluid tight packing 17 which engages the surface of the mandrel 10 for a purpose to be presently described.

A hollow cylinder 18 is connected to the lower end of the sleeve 15 by threaded or other suitable connections 19 and it is to be noted that the mandrel 10 terminates within the chamber 20 of the cylinder 18. The inner wall 21 of the cylinder 18 is provided with a plurality of circumferentially spaced axially extending grooves 22 which extend from the upper end of the chamber 20 to a point 23 substantially midway of the length. of the chamber 20. The purpose of these grooves 22 will be presently described.

A piston 24 is disposed in the chamber 20 of the cylinder 18 and is connected to the lower end of the mandrel 10 by screw threaded or other suitable connections 25. Depending from piston 24 is a guide sleeve 26 which projects downwardly through the lower end of the cylinder 18- and is engaged by a fluid tight packing 27. The piston 24 is provided with an annular shoulder 28 and spaced above the shoulder 28 are a plurality of annularly spaced abutments 29. A split piston ring 30 is disposed on the piston 24 between the shoulder 28 and the abutments 29 and the piston ring 30 engages the wall 21 of the chamber 20. A plurality of axially disposed grooves 31 are provided in the piston 24 inwardly of the piston ring 30 and as clearly shown in FIGS. 1a, 2a and 7, these grooves 31 extend from the upper surface of the shoulder 28 to a point above the abutments 29. The purpose of these grooves 31, as well as the split 32 in the piston ring 30 will be later described. A tubular member 33 is connected to the lower end of the mandrel by screw threaded or other suitable connections 34 and the tubular member 33 extends downwardly through the piston 24 and the guide sleeve 26. The passage 35 in the tubular member 33 communicates with the passage 14 in the mandrel '10. A drive sleeve 36 is connected to the lower end of the cylinder 18 by screw threaded or other suitable fastening means 37 and the drive sleeve 36 is provided at the lower end thereof with internal threads 38. The lower end surface 39 of the drive sleeve 36 is machined to the same helix angle as the threads 38 and projecting downwardly from the lower end surface 39 is a drive tooth 40.

A drive member 41 is rotatably mounted on the tubular member 33 and a reduced portion 42 on the upper end of the drive member 41 is provided with threads 43 threadedly engaging the threads 38in the drive sleeve 36. The reduced portion 42 of the drive member 41 terminates in a shoulder 44 which is machined to the same helix angle as the threads 43 and provided on the shoulder 44 is an upwardly extending drive tooth 45 which faces in the opposite direction from the drive tooth 40 on the drive sleeve 36. The lower end of the tubular member 33 is provided with a series of axially spaced flanges 46 which serve to engage suitable anti-friction washers 47 disposed in annular recesses 48 provided in a split sleeve 49 threadedly received in the lower end of the drive member 41. This serves to provide a thrust bearing connection between the drive member 41 and the tubular member 33 which results in coupling or connecting the drive member 41, the piston 24 and the mandrel 10 against relative axial movement with respect to each other. A lower pipe string coupling member 50 is secured to the lower end of the drive member 41 by screw threaded or other suitable connections 51 and at the lower end of the coupling member 50 there is provided a screw threaded projection 52 for threadedly engaging a pipe string or tool to which the tool of this invention is to be connected. The lower coupling member 50 is provided with an axial passage 53 extending therethrough and communicating with the passage 35 in the tubular member 33.

In operation, the chamber of the cylinder 18 is filled with a relatively non-compressible fluid and the head 11 of the mandrel 10 is coupled to the lower end of a pipe string by means of the threaded connection 12. The tool and pipe string are lowered into the well and the tool is coupled to a pipe string or tool which has become jammed in the well by means of the lower coupling member 50 and the threaded connection 52 thereon. At this time, the parts of the tool are in the relative positions shown in FIGS. 1a and lb, or in other words, with the piston 24 located at the lower end of the chamber 20 of the cylinder 18 and with the drive sleeve 36 spaced from the drive member 41 as clearly shown in FIG. 1b.

In order to place the tool of this invention in operation, the pipe string above the tool is rotated which operates to rotate the mandrel 10, the sleeve 15, cylinder 18 and drive sleeve 36 relative to the drive member 41 and lower coupling member 50. This results in the drive sleeve 36 moving downwardly as a result of the threaded engagement with the drive member 41 and this downward movement operates to move the cylinder 18 downwardly with respect to the piston 24, since the piston is held stationary by the tubular member 33 connected to the drive member 41 by means of the thrust bearing structure above described. Downward movement of the cylinder 18 with respect to the piston 24 will result in moving the piston ring 30 into engagement with the abutment 28 and compressing fluid in the chamber 20 of the cylinder 1.8v dis- 4 posed above the piston ring 30. Flow of fluid through the grooves 31 in the piston 24 will be prevented by engagement of the piston ring 30 with the abutment 28, in which case the piston ring 30 acts as a valve.

Since the fluid in the cylinder 18 is relatively noncompressible, a resistance to relative movement of the cylinder 18 and piston 24 will rapidly build up with the result that increasing torque is required on the drill string above the tool in .order to continue movement thereof. This will result in storing or accumulating energy in the drill string, and relatively slow movement of the cylinder 18 with respect to the piston 24 is permitted by reason of the fact that the fluid above the piston ring 30 will bleed through the slit 32 in the piston ring 30 which causes this structure to operate much in the nature of a dash pot. Downward movement of the cylinder 18 will continue at a relatively slow rate determined by the bleeding of fluid through the slit 32 in the piston ring 30 until such time as the piston ring 30 reaches the lower ends 23 of the grooves 22 in the inner wall of the cylinder 18, at which time considerable rotary energy has been accumulated in the drill string above the tool. As soon as the lower edge of the piston ring 30 passes the lower ends 23 of the grooves 22, fluid above the piston ring 30 will be released to flow from the upper part of the chamber 20 to the lower part thereof below the piston 24 which operates to suddenly reduce the pressure in the upper portion of the chamber 20, thereby permitting relatively rapid downward movement of the cylinder 18 and consequent rapid rotation of the drive sleeve 36. This rapid downward movement and rotation continues until the drive tooth 40 on the drive sleeve 36 engages the drive tooth 45 on the drive member 41 and since this is a sudden engagement, the impact occasioned thereby will transmit a relatively high rotary force to the lower coupling member 50 and to the pipe or tool coupled thereto. Reverse rotation of the pipe string above the tool of this invention conditions such tool for another similar operation and this is repeated until such time as the rotary impact forces delivered to the jammed tool or pipe are suflicient to free the same and permit recovery thereof.

It will, therefore, be seen that by the above described invention there has been provided a relatively simple, yet highly efficient tool for imparting a rotary impact force directly to a pipe or tool jammed in a well and in which the torque required to deliver such an impact force will be the same each time the tool is utilized, since such force is determined by the compression of fluid in the cylinder of the tool. Consequently, the torque required to operate the device can never exceed a safe value which is, of course, determined prior to placing the tool in operation.

During reverse movement of the tool to condition the same for further operation, it is to be noted that the cylinder 18 moves upwardly with relation to the piston 24 and this operates to raise the piston ring 30 from engagement with the abutment 28 which permits the flow of fluid from the lower portion of the chamber 20 through the grooves 31 to the upper portion of the chamber 20 above the piston 24. This position of the piston ring 30 is clearly shown in FIG. 7.

The tool of this invention is entirely self-contained and requires no auxiliary equipment and may be utilized with conventional well equipment and pipe strings without modification thereof.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. A rotary jar type well tool comprising an elon gated mandrel, an enlarged head at the upper end of said mandrel, a threaded bore in said head for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, inter-engaging splines on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing seated in a groove in said sleeve adjacent the lower end of said sleeve and sealingly engaging said mandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an elongated guide sleeve on said piston extending downwardly through the lower end of said cylinder, a fluid tight packing seated ina groove in said cylinder adjacent the lower end of said cylinder and sealingly engaging said guide sleeve to prevent fluid flow between said cylinder and said guide sleeve, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending, from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from substantially the midpoint of said cylinder to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston and guide sleeve, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, a thrust bearing connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

2. A rotary jar type well tool comprising an elongated mandrel, an enlarged head at the upper end of said mandrel, a threaded bore in said head for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, inter-engaging splines on said mandrel andsleeve for preventing relative rotation therebetween, afluid tight packing on said sleeve sealingly engaging said rnandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within-said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an elongated guide sleeve on said piston extending downwardly through the lower endof said cylinder, a fluid tight packing on said cylinder sealingly engaging said guide sleeve to prevent fluid flow between said cylinder and said guide sleeve, an annular shoulder on said piston, circumferentially' spaced abutments on said' piston axially spaced above said shoulder, a split piston ring on said piston movable betweensaid shoulder and said abutments and engaging the inner wallof said cylinder, axially disposed grooves in said piston inwardly of said ringand extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from substantially the midpoint ofsaid cylinder to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston and guide sleeve, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive toothon the lower end of said drive sleeve, a drive member rotatably mounted on said tubular mem ber, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder, and threadedly engaging said drive sleeve,- a drive tooth projecting upwardly from said last named shoulder, a thrust bearing connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, saiddrive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

3. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, inter-engaging splines on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve sealingly engaging said mandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an elongated guide sleeve on said piston extending downwardly through the lower end of said cylinder, a fluid tight packing on said cylinder sealingly engaging said guide sleeve to prevent fluid flow between said cylinder and said guide sleeve, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments, and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending substantially from the midpoint of said cylinder to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston and guide sleeve, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth at the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, a thrust bearing connecting said tubular member and said drive member and a lower pipestring couplingmember secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumlated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member. to the pipe string below said tool.

4. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve sealingly engaging said mandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an elongated guide sleeve on said piston extending downwardly through the lower end of said cylinder, at fluid tight packing on said cylinder sealingly engaging said guide sleeve to prevent fluid flow between said cylinder and said guide sleeve, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from substantially the midpoint of said cylinder to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston and guide sleeve, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, a thrust bearing connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

5. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve 8 sealingly engaging said mandrel to prevent fluid flow be tween said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder from a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending substantially from the midpoint of said cylinder to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, and a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, 3. downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular memher, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, a thrust bearing connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in said cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulating in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

6. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve sealingly engaging said mandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth at the lower end of 'said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded piston extend ing upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, a

thrust bearing connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulating in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

7. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said man drel, means on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve sealingly engaging said mandrel to prevent fluid flow between said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, said mandrel terminating within said cylinder, a piston disposed in said cylinder and connected to the lower end of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, means rotatably connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will he suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

8. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a fluid tight packing on said sleeve sealingly engaging said mandrel to prevent fluid flow be tween said sleeve and said mandrel, a hollow cylinder connected to the lower end of said sleeve, a piston dis- .posed in said cylinder and connected to the lower end'of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, means rotatably connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulat ing in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

9. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a hollow cylinder connected to the lower end of said sleeve, a piston disposed in said cylinder and connected to the lower end of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a split piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to a point above said abutments, axially disposed grooves in the inner wall of said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, means rotatably connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will he suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

10. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a hollow cylinder connected to the lower end of said sleeve, a piston disposed in said cylinder and connected to the lower end of said mandrel, an annular shoulder on said piston, circumferentially spaced abutments on said piston axially spaced above said shoulder, a piston ring on said piston movable between said shoulder and said abutments and engaging the inner wall of said cylinder, axially disposed grooves in said piston inwardly of said ring and extending from said shoulder to the point above said abutments, means on said piston to bleed pressure fluid from above said piston to below said piston, axially disposed grooves in the inner wall of said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, means rotatably connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fluid in said cylinder above said piston ring to progressively slow rotary and downward movement and accumulate energy in the pipe string above said tool, and upon said piston ring reaching the grooves in the cylinder wall, pressure in the upper portion of said cylinder will be suddenly released thereby releasing the energy accumulated in said pipe string to cause rapid rotation and downward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

11. A rotary jar type well tool comprising an elongated mandrel, means for detachably coupling said mandrel to a pipe string, a sleeve slidably received on said mandrel, means on said mandrel and sleeve for preventing relative rotation therebetween, a hollow cylinder connected to the lower end of said sleeve, a pistonvdisposed in said cylinder and connected to the lower end of said mandrel, a piston ring on said piston engaging the inner wall of said cylinder, means on said piston to bleed pressure fluid from above said piston to below said piston, valve means on said piston to prevent flow of pressure fluid from above to below said piston during movement of said piston in one direction and to permit flow of pressure fluid from below to above said piston during movement in the opposite direction, axially disposed grooves in the inner wallof said cylinder extending from a point intermediate the ends to the upper end, a tubular member connected to the lower end of said mandrel and extending downwardly through said piston, a drive sleeve connected to the lower end of said cylinder, internal threads at the lower end of said drive sleeve, a downwardly projecting drive tooth on the lower end of said drive sleeve, a drive member rotatably mounted on said tubular member, an annular shoulder on said drive member, a reduced threaded portion extending upwardly from said last named shoulder and threadedly engaging said drive sleeve, a drive tooth projecting upwardly from said last named shoulder, means rotatably connecting said tubular member and said drive member and a lower pipe string coupling member secured to the lower end of said drive member, whereby upon rotation of said mandrel in one direction to rotate said sleeve, said cylinder and said drive sleeve, said drive sleeve will move downwardly on the threaded portion of said drive member and move said cylinder downwardly with respect to said piston to compress fiuid in said cylinder above said piston ring to progressively slow rotary and downward movement and acward movement of said drive sleeve until said drive teeth engage with an impact, such impact being transmitted through said drive member and said lower coupling member to the pipe string below said tool.

References Cited in the file of this patent UNITED STATES PATENTS 875,516 Freeland Dec. 31, 1907 1,650,301 Risher Nov. 22, 1927 1,304,700

Maxwell May 12, 1931 

